The present invention relates to an axial blower of the type known from VGB-Kraftwerkstechnik 15, 159-165 (1977). The breakaway of the medium flowing through this known blower can be decreased at lower volumes. The backstreaming that occurs at the outside diameter of the impeller is locally stabilized in an annular bypass channel, with diversion blades in the annular channel straightening out the twist that occurs within the backstreaming.
Another axial blower is known from International Patent Application No. WO 85/00640. The diversion blades inside the annular channel are curved. Axial blowers with diversion blades of this type are expensive to manufacture.